1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
---|---|
2 | |
3 | #ifndef LINUX_RESUME_USER_MODE_H |
4 | #define LINUX_RESUME_USER_MODE_H |
5 | |
6 | #include <linux/sched.h> |
7 | #include <linux/task_work.h> |
8 | #include <linux/memcontrol.h> |
9 | #include <linux/blk-cgroup.h> |
10 | |
11 | /** |
12 | * set_notify_resume - cause resume_user_mode_work() to be called |
13 | * @task: task that will call resume_user_mode_work() |
14 | * |
15 | * Calling this arranges that @task will call resume_user_mode_work() |
16 | * before returning to user mode. If it's already running in user mode, |
17 | * it will enter the kernel and call resume_user_mode_work() soon. |
18 | * If it's blocked, it will not be woken. |
19 | */ |
20 | static inline void set_notify_resume(struct task_struct *task) |
21 | { |
22 | if (!test_and_set_tsk_thread_flag(tsk: task, TIF_NOTIFY_RESUME)) |
23 | kick_process(tsk: task); |
24 | } |
25 | |
26 | |
27 | /** |
28 | * resume_user_mode_work - Perform work before returning to user mode |
29 | * @regs: user-mode registers of @current task |
30 | * |
31 | * This is called when %TIF_NOTIFY_RESUME has been set. Now we are |
32 | * about to return to user mode, and the user state in @regs can be |
33 | * inspected or adjusted. The caller in arch code has cleared |
34 | * %TIF_NOTIFY_RESUME before the call. If the flag gets set again |
35 | * asynchronously, this will be called again before we return to |
36 | * user mode. |
37 | * |
38 | * Called without locks. |
39 | */ |
40 | static inline void resume_user_mode_work(struct pt_regs *regs) |
41 | { |
42 | clear_thread_flag(TIF_NOTIFY_RESUME); |
43 | /* |
44 | * This barrier pairs with task_work_add()->set_notify_resume() after |
45 | * hlist_add_head(task->task_works); |
46 | */ |
47 | smp_mb__after_atomic(); |
48 | if (unlikely(task_work_pending(current))) |
49 | task_work_run(); |
50 | |
51 | #ifdef CONFIG_KEYS_REQUEST_CACHE |
52 | if (unlikely(current->cached_requested_key)) { |
53 | key_put(current->cached_requested_key); |
54 | current->cached_requested_key = NULL; |
55 | } |
56 | #endif |
57 | |
58 | mem_cgroup_handle_over_high(GFP_KERNEL); |
59 | blkcg_maybe_throttle_current(); |
60 | |
61 | rseq_handle_notify_resume(NULL, regs); |
62 | } |
63 | |
64 | #endif /* LINUX_RESUME_USER_MODE_H */ |
65 |